This invention relates to cancer research and treatment and, more particularly, to methods for distinguishing normal, neoplastic, and transformed, i.e., tumor, cells for observation and selective treatment.
There are many needs in cancer research, diagnosis, and treatment to distinguish normal, neoplastic, and transformed cells. As used herein, the term "transformed cells" means cells that are undergoing or have undergone neoplastic transformation. In research it would be useful to determine the onset of cell transformation; e.g., rodent cells can undergo a spontaneous transformation and it would be highly desirable to verify that a particular culture is free of transformed cells at the beginning of an experiment. Research needs also require that transformed cell lines be developed and characterized for investigation. The development of such cell lines would be enhanced if the growth of normal cells could be suppressed to allow the outgrowth of transformed cells. Likewise, patient tissue assays may contain only a few transformed cells within the population of normal cells. The transformed cells are difficult to distinguish from the normal cells using conventional techniques. In accordance with the present invention, transformed cells can be caused to have preferential growth over normal cells so that the presence of a small number of transformed cells can be determined by subsequent large colonies.
In cancer chemotherapy, chemotherapeutic agents are used to kill transformed cells. However, the chemical agents also kill normal cycling cells and create highly undesirable side effects. In accordance with another aspect of the present invention, normal cells may be arrested in G.sub.1 phase of the cell cycle and thus protected from the effects of a selected therapeutic agent that kills the cycling cancer cells. In this case the therapy regimen may be designed for optimum killing of transformed cells.
Accordingly, it is an object of the present invention to provide a process for arresting the growth of normal cells without affecting the growth of transformed cells.
It is another object of the present invention to reversibly arrest the growth of normal cells without affecting the growth of transformed cells.
Yet another object is to reversibly arrest the growth of normal cells in G.sub.1 phase of the cell cycle so that they are protected from the effects of chemotherapeutic agents directed to killing the cycling transformed cells.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.